Life was pretty quiet on Earth 600 million years ago. But sometime between then and 500 millions years ago, something happened, and plant and animal life went through an astounding run of diversification and evolution - the Cambrian explosion
. For as long as scientists have known about it, we've wondered why and how the explosion happened - it seems strange that things would be so stable and then just start changing so abruptly. Well, some researchers think they may have an answer: the collisions of Arabia, India, and Antarctica with other land masses at the time, and the mountains they raised, seem to have released great quantities of nutrient-rich sediments into the sea, giving life the materials it needed to evolve
. This is a really fascinating idea, and if it pans out it could explain quite a bit.
In our own time, we have become quite concerned about fast-evolving pathogens, like the flu virus. In 1918, a mutant strain of the flu caused millions of deaths all across the world, and as H5N1 spreads today, health worker are worried that it could change, and instantly become another number-one-killer
. So, researchers at the CDC reconstructed the deadly 1918 strain, and have been examining its effects. It seems that that flu is so deadly because it incites a major immune overreaction in hosts
- their own systems kill them trying to get at the virus! Learning how 1918 flu works will hopefully help us predict, treat, and prevent future pandemics.